Gene Expression, Non-Coding RNA, and Circular RNA Alterations in Patients with T-Prolymphocytic Leukemia.

Background/Objectives: Identifying molecular liabilities and understanding disease heterogeneity are prerequisites for advancing therapies in T-cell prolymphocytic leukemia (T-PLL), a rare T-cell malignancy with a poor prognosis. Methods: RNA-seq profiling of T-PLL samples (n = 10) and the normal counterpart (n = 5) allowed us to report gene expression and pathway alterations in malignant cells, revealing that non-coding, antisense and circular RNA expression is profoundly altered in T-PLL. Results: T-PLL displayed activation of several oncogenic pathways, particularly PI3K/AKT/mTOR and Wnt, suppression of healthy T-cell activities and cell death escape. Tumor suppressor lncRNAs (NEAT1, MIAT and LUCAT1) with reduced expression and upregulated oncogenic pro-proliferative lncRNAs (FIRRE, TERC, XIST and PVT1) were identified. CircRNAs ectopically expressed in T-PLL included circSEMA4B and circSATB1, linked to the Wnt pathway, circFIRRE and oncogenic circPVT1 and circFKBP5. Focusing on five genes with validated recurrent oncogenic variants (STAT5B, JAK3, ATM, KMT2C, and ARID1A), we investigated genotype/phenotype relations. A multiple predictor linear model suggested potential links between driver variants and alterations in gene and circRNA expression, including association between STAT5B mutations and LTF upregulation, JAK3 lesions and increased PLXNA4 expression along with CCR4 suppression. Conclusions: Our transcriptomic profiling and genotype-phenotype association analysis identified specific genes, non-coding RNAs, pathways and candidate genotype-associated transcriptional signatures that warrant further investigation as potential targets for the development of new therapeutic approaches for this rare and heterogeneous malignancy.